Heat oven to 190C/170C fan/gas 5. Butter two 20cm sandwich tins and line with baking paper. In a large bowl, beat all the cake ingredients together until you have a smooth, soft batter.

Divide the mixture between the tins, smooth the surface with a spatula or the back of a spoon then bake for about 20 mins until golden and the cake springs back when pressed. Turn onto a cooling rack and leave to cool completely.

To make the filling, beat the butter until smooth and cream, then gradually beat in icing sugar and then vanilla extract. Spread the buttercream over the bottom of one of the sponges, top it with the jam and sandwich the second sponge on top. Dust a little icing sugar on top before serving.